Effects of selective dopamine D1 and D2 antagonists on male rat sexual behavior

Summary The effects of selective dopamine (DA) D₁ and D₂ antagonists on male rat sexual behavior were investigated. The D₁ antagonist (+)SCH-23390, 25–100 g kg^–1 s.c. –20 min, and the D₂ antagonist raclopride, 0.1–1.6 mg kg^–1 s.c., –20 min, decreased both the number of mounts and intromissions preceding ejaculation. No statistically significant effects in the time up to ejaculation or in the time up to the first intromission were noted, whereas both compounds produced a statistically significant increase in the post-ejaculatory interval. The effect can generally be characterized as psychomotor inhibition, and no evidence was obtained for a specific role of DA D₁ or D₂ receptors in the mediation of male rat sexual behavior.The expert technical assistance of Ms Elisabeth Wallin is gratefully acknowledged. The figures were skilfully prepared by Ms Madelene Kröning at the Department of Psychology. This study received support from the Bank of Sweden tercentenary Foundation, The Swedish MRC and Wilhelm and Martina Lundgren Foundation.     

Der Einfluss der experimentellen Leberschädigung auf Gesamtfett und ungesättigte Fettsäuren in Serum und Leber

Summary In experiments on rats with CCl₄-induced liver damage the total lipids and the di- to tetra-enoic fatty acids were estimated. The acute experiment of 72 h duration showed a strong augmentation of total lipids and a transitory diminution of arachidonic acid in serum and liver which two months after the intoxication still persisted together with a marked rise in linolenic acid. The parallelism of changes of saturation of the fatty acids in serum and liver being statistically significant indicates that the process of desaturation is most probably localized in the liver itself.     

Leptin, but not a β3-adrenergic agonist, upregulates muscle uncoupling protein-3 messenger RNA expression: short-term thermogenic interactions

The short-term effects of leptin and a β₃-adrenoceptor agonist on thermogenesis and expression of uncoupling proteins (UCPs) in brown adipose tissue (BAT) and muscle and their possible interactions were assessed. One hour after administration of the β₃-adrenoceptor agonist Trecadrine, a statistically significant increase in UCP1 messenger RNA (mRNA) expression in BAT was observed, whereas UCP2 and UCP3 in both BAT and gastrocnemius muscle were unaffected. Leptin induced an upregulation of UCP3 mRNA in muscle, with no changes in BAT UCP1 mRNA. A statistical interaction was found between leptin and Trecadrine in rectal temperature. The present study provides evidence, for the first time, of the induction of UCP3 mRNA expression in skeletal muscle by leptin in nongenetically obese animals. Received 5 March 1999; received after revision 19 April 1999; accepted 21 April 1999     

Effects of female sex hormones on polyamine-oxidizing enzyme activities and polyamine concentrations in immature rat uterus and liver

17-estradiol (E₂) and progesterone (P) treatment of immature female rats (10 g/100 g body weight) respectively resulted in 1.38-fold (p<0.02) and 1.42-fold (p<0.02) increase in the uterine polyamine oxidase activity, and 2.45-fold (p<0.001) and 1.43-fold (p<0.02) increase in the uterine diamine oxidase activity, as compared to the controls. E₂ caused a 5-fold (p<0.05) and a 1.36-fold (p<0.05) increase in putrescine and spermidine concentration respectively in rat uterus. Increases of 1.7-fold (p<0.02) and 1.6-fold (p<0.05) in putrescine and spermine concentration were determined in the P-treated uterus, as compared to the controls. The spermidine/spermine ratio, which is regarded as an index of growth rate, was higher in the E₂-treated uterus and lower in the P-treated uterus than in the control uterus. No statistically significant hormonal effects were estimated in the immature liver. The data reported suggest the possibility of an involvement of polyamine-oxidizing enzymes in the modulation of polyamine concentrations in rat uterus by the female sex hormones.     

Impact of Macroeconomic Announcements on US Equity Prices: 2009–2013

Returns of several US equity exchange‐traded funds on the days of major macroeconomic announcements are examined for the period of January 2009 to July 2013. The ARMA+GARCH model with external linear regression terms that describe announcement events and their surprises is used. It is found that mean daily returns may be notably higher on the announcement days than those for the buy‐and‐hold strategy, though their difference may be not statistically significant. The ISM Manufacturing Reports, Non‐Farm Payrolls, International Trade Balance, Index of Leading Indicators, Housing Starts, and Jobless Claims turn out to be the most statistically significant factors in the model. Three trading strategies that realize daily returns on the various macroeconomic announcement days are compared with the buy‐and‐hold strategy. The choice of announcements with statistically significant regression coefficients yields higher mean daily returns and better Sharpe ratios but possibly lower compound returns. Transaction costs may significantly affect profitability of these trading strategies. Copyright © 2015 John Wiley & Sons, Ltd.     

Is there a cost to being socially responsible in investing?

In this study we address three questions concerning socially responsible investing. First, is the average return of a socially screened equity universe statistically different from the average return of an unscreened universe for the 1987–94 period? Second, do analysts' earnings per share forecasts aid a manager in selecting stocks in socially screened and unscreened universes? Third, can one use an expected return model incorporating both value and growth components to select stocks and create portfolios in the socially screened and unscreened equity universes such that one can outperform both universe benchmarks? We find no statistically significant differences in the mean returns of unscreened and screened equity universes for the 1987–94 period. Earnings forecasts and the knowledge of those forecasts add value in the creation of portfolios. We find few statistically significant differences in the predictive power of the composite model to select stocks in both unscreened and screened equity universes. The estimated composite model offers the potential for substantial outperformance of socially screened and unscreened equity universes. © 1997 John Wiley & Sons, Ltd.     

Congressus

Summary The number of penicillin-resistant organisms among a certain population ofStaph. aureus can be reduced by treatment with crystalline desoxyribonuclease. These results are statistically significant.     

Hydroxyprolin-Ausscheidung im Rattenharn nach Injektion von Schlangengift

Summary In rats, a statistically significant increase in hydroxyproline excretion occurs following injection of crotalus toxin (Agkistrodon piscivorus Lacépède). The significance of this finding is briefly discussed.     

The negative correlation between erythrocyte concentration and mean corpuscular haemoglobin or mean corpuscular volume in normal dogs

Summary In normal adult Beagle dogs red cell concentration decreased linearly with increasing mean red cell volume and mean red cell haemoglobin. The results are statistically significant (p<0.001).     

Die durch animalische Mucoproteine verursachte Wachstumshemmung

Summary Anti-growth activity of animal mucoproteins on germinating seeds ofLupinus albus was tested; the inhibition with plasma mucoprotein was statistically significant. The inhibition with urine mucoprotein according toAnderson was the most effective.     

Effect of prostaglandin E1 on rat gastric motility and cyclic nucleotide content

Summary Administration of exogenous prostaglandin E₁ resulted in an increase in contractility of rat fundic muscle measured in vivo; a significant decrease in fundic tissue levels of cyclic-adenosine monophosphate and a significant increase in cyclic-guanosine monophosphate.     

Does the moon influence the predatory activity of mites?

Periodicity in predatory activity was observed in overwintered females ofTyphlodromus pyri Scheuten (Acari: Phytoseiidae). Chronobiometrical analysis revealed that an approximately circabiseptan (about-14-day) rhythm is statistically significant, with a striking depression around the full moon.     

The effect of dietary fat on the anticoagulant activity of aflatoxin B1

Summary A single i.p. dose of aflatoxin B₁ had no significant effect on the thrombotest clotting times of monkeys subsisting on low-fat and high-fat dietary regimens, respectively. There was a significant interaction between aflatoxin and dietary fat level.     

Effects of myocardial ischemia and reperfusion on mitochondrial function and susceptibility to oxidative stress

We investigated the effects of ischemia duration on the functional response of mitochondria to reperfusion and its relationship with changes in mitochondrial susceptibility to oxidative stress. Mitochondria were isolated from hearts perfused by the Langendorff technique immediately after different periods of global ischemia or reperfusion following such ischemia periods. Rates of O₂ consumption and H₂O₂ release with complex I- and complex II-linked substrates, lipid peroxidation, overall antioxidant capacity, capacity to remove H₂O₂, and susceptibility to oxidative stress were determined. The effects of ischemia on some parameters were time dependent so that the changes were greater after 45 than after 20 min of ischemia, or were significantly different to the nonischemic control only after 45 min of ischemia. Thus, succinate-supported state 3 respiration exhibited a significant decrease after 20 min of ischemia and a greater decrease after 45 min, while pyruvate malate-supported respiration showed a significant decrease only after 45 min of ischemia, indicating an ischemia-induced early inhibition of complex II and a late inhibition of complex I. Furthermore, both succinate and pyruvate malate-supported H₂O₂ release showed significant increases only after 45 min of ischemia. Similarly, whole antioxidant capacity significantly increased and susceptibility to oxidants significantly decreased after 45 min of ischemia. Such changes were likely due to the accumulation of reducing equivalents, which are able to remove peroxides and maintain thiols in a reduced state. This condition, which protects mitochondria against oxidants, increases mitochondrial production of oxyradicals and oxidative damage during reperfusion. This could explain the smaller functional recovery of the tissue and the further decline of the mitochondrial function after reperfusion following the longer period of oxygen deprivation. Received 18 May 2001; received after revision 17 July 2001; accepted 24 July 2001     

Age-dependent tolerance toBaculovirus in last larval instars of the codling moth,Cydia pomonella,L., induced either for pupation or for diapause

Summary LD₅₀ values as well as time-dependent parameters of granulosis virus infections were determined at different times during the last larval instar (L₅) of the codling moth,Cydia pomonella L., induced either for pupation or for diapause. A significant increase of tolerance to virus was found in 48-h-old L₅ induced for pupation, and 24 h later in L₅ induced for diapause.     

Interchange trisomics in pearl millet

Summary In the progeny of interchange heterozygotes ofPennisetum typhoides, 2 interchange trisomic plants were obtained. These were selfed over 2 generations and the cytology of the parents, s₁ and s₂ plants was studied. The types of multiple associations in the s₁ and s₂ generations differed from those of the parent. A significant decrease in mean chiasma frequency was noted in s₁ and s₂.Acknowledgment. The author is grateful to Prof. em. J. V. Pantulu, Department of Botany, Andhra University, Waltair, for his suggestions and encouragement.     

Hormone and forskolin-stimulated cyclic AMP accumulation in human lymphocytes: reliability of longitudinal time measurements

Summary Reliability of measurement of lymphocyte cyclic AMP synthesis in intact cells was estimated by taking 3 successive blood samples during a one-month period from 11 healthy volunteers. Isoproterenol and prostaglandin E₁-stimulated cyclic AMP accumulation were used to evaluate the activity of these two receptor activities in human lymphocytes. Forskolin-stimulated cyclic AMP accumulation was used to evaluate the activity of the Ns/catalytic subunit. Only for forskolin was significant reliability observed. For isoproterenol and prostaglandin E₁ significant reliability was observed only for male subjects.Acknowledgment. This work was supported in part by the following organizations: Chief Scientist's Office, Israel Ministry of Health; Herman Goldman Foundation, New York; United Jewish Endowment Fund of Greater Washington-Pollinger Foundation.     

Effects of anaesthesia and chronic catheterization on circulating levels of prostaglandins (PGE2 and PGF2a in dogs

Summary Chronic catheterization of aorta and inferior vena cava in dogs did not significantly affect circulating levels of prostaglandins (PGE₂ and PGF_2a ). Pentobarbital (30 mg/kg i.v.) anaesthesia produced a significant decrease in PGF_2a .This work was supported by INSERM (grant No. 76.5.183.5).We wish to thank Miss Laure Eloy and Mrs Annick Soubrier for their technical assistance.     

Vitamin E,catalase, manganous or cobaltous ions and dithiothreitol protect against Tween 20-induced hemolysis of vitamin E-deficient chick and kid erythrocytes

Summary The effective Tween 20 concentration at which 70% hemolysis was achieved in vitro correlated with the plasma vitamin E content of chicks (r=0.85). Addition of catalase, MnCl₂, CoCl₂ or dithiothreitol in vitro showed significant protection against the hemolysis induced by Tween 20 in vitamin E-deficient chick and kid erythrocytes.     

Reciprocal changes in serum free thyroxine fraction and thyrotropin level after administration of thiocyanate to rats

Summary The administration of thiocyanate to rats caused a significant increase of serum free thyroxine fraction, which coincided with the significant decrease of TSH level. The other components (AFT₄, T₄, T₃) in serum at this time were decreased or unchanged. The finding suggests the role of free thyroxine fraction in feed-back regulation of TSH secretion.Acknowledgment. We thank Dr A. Parlow and the NIAMDD, Rat Pituitary Hormone Distribution Program, for material for rat TSH immunoassay; Dr J. Nauman (Inst. Postgrad. Med., Warsaw, Poland) for T₃ antibody, and to Ing. J. Sadlo, Mrs M. t'astná and Miss R Fajkoová for technical assistance.